Recently, as the intelligence of touch products and mobile products is more and more popular, the image quality of a small-size thin film transistor-liquid crystal display (TFT-LCD) becomes especially important.
FIG. 1 is a sectional view showing a peripheral part of a liquid crystal display module (for clear illustration, the structures that are not associated with the present invention are not shown), which mainly comprises a bezel 100, a color filter glass substrate 201, an array substrate (including TFT) 300, a light-shielding black matrix (BM) 202 on the color filter glass substrate 201, a common electrode 203 (made of Indium Tin Oxide, ITO), a sealant 400 and a backlight unit (BLU) 500. As shown in FIG. 1, an angle α between a line from an outer edge (the edge approaching the bezel) of the black matrix 202 to an inner edge (the edge approaching a liquid crystal panel) of the bezel 100 and a vertical direction (a direction perpendicular to the liquid crystal panel) is a normal visual field of a LCD screen, and within the visual field, an observer can normally see an image on the display screen, without light leakage at the edge of the liquid crystal display module. Opposite to the visual field, at an angle β between a line from the outer edge of the black matrix 202 to the inner edge of the bezel 100 and a horizontal direction (a display surface of the liquid crystal panel), the observer can see the light from a backlight source of the liquid crystal display module, i.e., there is light leakage at the edge of the liquid crystal display module. Currently, when designing a TFT-LCD, the smaller the angle β between the line from the outer edge of the black matrix 202 to the inner edge of the bezel 100 and the display surface of the liquid crystal display module is, the smaller is the probability of the light leakage at the edge of the liquid crystal display module, and the better is the image quality.
Currently, two methods are mainly adopted to improve the light leakage at the edge of the liquid crystal display module. One method includes extending the bezel 100 toward the display region of the liquid crystal panel as possible, so as to cover the display region. However, such a design is against a current trend of a narrow bezel 100. The other method includes extending the black matrix 202 toward the bezel 100, as shown in FIGS. 2 and 3. Referring to FIG. 2, the black matrix 202 extends toward the bezel 100, and the black matrix 202 partially covers the sealant 400. Referring to FIG. 3, the black matrix 202 extends toward the bezel 100, and the black matrix 202 fully covers the sealant 400. However, the black matrix 202 may merely be extended over a limited distance so as not to cover an area greater than that of the color filter glass substrate 201. Especially at the portion of a circuit terminal of the liquid crystal display module (a region where a signal is applied from an external circuit to the LCD screen), the black matrix 202 cannot cover a terminal region of an array glass substrate 301. Meanwhile, when the sealant 400 is designed to be partially or fully covered by the black matrix 202, the reliability of the entire liquid crystal display module will be reduced, because a contact force between the common electrode 203 and the color filter glass substrate 201 is greater than a contact force between the black matrix 202 and the color filter glass substrate 201. When the liquid crystal display module undergoes a high temperature or an impact, the black matrix 202 may fall away from the common electrode 203, and finally the glass substrate may be separated therefrom. As a result, the quality of the liquid crystal display module will be seriously affected.